1. Field of the Invention
The present invention relates to power supplies of a system and, more particularly, to a system such as an embedded system that has multiple power supplies that are synchronized during initialization of the system.
2. Description of the Related Art
In recent years, systems that use microcontrollers have begun to use multiple power supplies to supply power to the microcontroller. The use of multiple power supplies has created problems in the microcontroller circuitry because, by their nature, power supplies are difficult to time in the ramping of the multiple power signals. During the power up sequence of a system, due to the multiple power supplies, the microcontroller is prone to sending erroneous signals to other circuitry of the system.
For example, in the automotive industry, a microcontroller that is powered by multiple power supplies often has output buffers that erroneously drive other devices that are external to the microcontroller such as fuel injectors, relays, etc. To overcome this problem, designers of such automotive systems have been forced to design around the problem created by multiple power supplies on the system board itself. It would be desirable to modify control circuitry to accommodate the multiple power supplies without being forced to design around the multiple power supplies on the system board itself.